Method of manufacturing contact lenses

ABSTRACT

This invention relates to a method of manufacturing contact lenses. The method includes enclosing first and second lens blanks in a protective magazine, unloading the lens blanks from the magazine, machining the lens blanks, enclosing the machined lens blanks in another protective magazine, and then transferring this magazine to another machine tool.

This application is a continuation of application Ser. No. 589,061,filed Jan. 11, 1984.

This invention relates to a method of, and apparatus for manufacturingcontact lenses.

The most commercially important method of manufacturing contact lensesat present is by machining from suitably sized lens blanks. Although thelens blanks are commonly machined on automatic or semi-automatic lathes,the manufacturing process is necessarily somewhat laborious, since thelens blanks have to be loaded by hand into the lathe collet, andunloaded by hand after the sequence of machining operations has beencompleted. A typical machining method and lens manufacturing apparatusare described in British Patent Specification No. 1,488,001. There isconsequently a need for a method of automatically loading workpieces,such as contact lens blanks to a machine tool, and for apparatussuitable for this operation

Furthermore the manufacture of contact lenses involves a series ofoperations in which the lens surfaces are polished after lathe cuttingsteps in which the base and power curves are formed and the finishedlenses are then inspected for quality and reference to specification.These operations are difficult to carry out accurately and repetitivelysince, according to conventional procedures, each lens is handledindividually.

According to one aspect of the present invention, there is provided amethod of machining workpieces, especially contact lens blanks, themethod comprising the steps of feeding the workpieces sequentially froma magazine to a loading station, at which each workpiece is positionedaccurately in a predetermined location with respect to a machine toolcollet, transferring each of the workpieces from the loading station tothe collet, and machining a surface on each of the workpieces.

The invention also provides apparatus for feeding workpieces to amachine tool collet, the apparatus comprising a loading device and amagazine for containing a plurality of workpieces, the magazine havingan opening at one end through which the workpieces are sequentiallyremovable, the loading device being arranged to accept workpiecessequentially from the magazine at loading station and to feed them tothe collet of a machine tool, the loading device having means forholding a workpiece removed from the magazine and means for positioningsaid workpiece at the loading station in a predetermined position withrespect to the collet, and the loading device having a mechanism formoving the holding means so as to carry said workpiece from the loadingstation to the machine tool collet.

By designing a magazine for the lens blanks and providing similarloading and unloading devices on each of the machines employed for thedifferent stages of lens manufacture, the magazines containing lensblanks or partly worked blanks can readily be taken from one machine tothe next, with the minimum of handling. Higher productivity with greateraccuracy and repeatability can thereby be achieved.

Thus, although the loading and unloading devices using a magazine willbe described in greater detail as applied to the automatic feeding oflens blanks to a lens lathe, and for removing the machined workpiecesafter the machining operation, the loading and unloading systemdescribed herein is applicable to other operations in the manufacture oflenses for example, feeding lenses or partly-worked blanks to apolishing machine. However, in the case of feeding blanks to a lathethere is normally a need for precise determination of the position of awork-piece with respect to the collet, while feeding of lenses topolishing machines does not require the same degree of accuratepositioning of the lenses.

Advantageously, the loading device has a carriage which supports theholding means, and the carriage is movable by at least onepiston-and-cylinder device. Preferably, the carriage is movable by firstand second piston-and-cylinder devices, the first and secondpiston-and-cylinder devices being jointly effective to move the holdingmeans from the loading station into a position in which said workpieceis in alignment with the collet, the first piston-and-cylinder devicebeing effective to move the holding means so as to carry said workpiecefrom said piston to the machine tool collet, and the secondpiston-and-cylinder device being effective to move the holding meansaway from the collet after said workpiece has been transferred to thecollet. Conveniently, the piston-and-cylinder devices are arrangedsubstantially at right-angles, and wherein the carriage is provided witha cam which is movable along a cam surface for guiding the holding meansfrom the loading station to the collet.

In a preferred embodiment, the piston-and-cylinder devices arecontrolled by first and second proximity switches, the first proximityswitch initiating the movement of the holding means which carries saidworkpiece from said position towards the collet, and the secondproximity switch initiating movement of the holding means away from thecollet after said workpiece has been transferred to the collet.

In another preferred embodiment, each of the piston-and-cylinder deviceshas a magnet associated with its piston rod and a sensor associated withits cylinder, the magnets and sensors being so positioned that, when thesensor of the second piston-and-cylinder device is in alignment with themagnet of that device, it initiates the movement of the holding meanswhich carries said workpiece from said position towards the collet, and,when the sensor of the first piston-and-cylinder device is in alignmentwith the magnet of that device, it initiates the movement of the holdingmeans away from the collet after said workpiece has been transferred tothe collet.

Preferably, the apparatus further comprises a delay switch which delaysactuation of the first piston-and-cylinder device for a predeterminedtime after the actuation of the second piston-and-cylinder device at thestart of the movement of the holding means from the loading station tosaid position.

Advantageously, the holding means comprises a pair of star wheels.Preferably, each of the star wheels is rotatably mounted on the loadingdevice by means of a respective one-way clutch, the star wheels beingarranged to grip generally cylindrical workpieces as they are releasedfrom the magazine.

In a preferred embodiment, the positioning means is constituted by apositioning lever mounted on the loading device, the positioning leverhaving a gauging surface arranged to contact a surface of a workpiece,and thereby to position the workpiece accurately in a predeterminedlocation for engagement by the star wheels.

In another preferred embodiment, the positioning means is constituted bya device having a stop pin which is arranged to contact one of the sidefaces of one of the star wheels, and thereby to position a workpieceaccurately in a predetermined location between the star wheels.Conveniently, the positioning device is fixed with respect to themagazine. Advantageously, the stop pin is resiliently mounted within thepositioning device.

The apparatus may further comprise an unloading device arranged toaccept workpieces sequentially from the collet, and for moving theworkpieces away from the collet. Preferably, the unloading device isidentical with the loading device except that it is not provided withpositioning means. In this case, the one-way clutches of the unloadingdevice permit rotation of the star wheels of the unloading device indirections opposite to those in which the one-way clutches of theloading device permit rotation of the equivalent star wheels of theloading device.

The invention also provides a lens lathe comprising a head stock, acollet rotatably mounted in the head stock, and apparatus for feedingworkpieces to the collet, the feeding apparatus being as defined above.

The invention further provides a magazine for use with the feedingapparatus defined above, the magazine being adapted to contain aplurality of workpieces, and having an opening at one end through whichthe workpieces are sequentially removable, the magazine being providedwith a releasable locking device adjacent said one end, the lockingdevice being engageable with the workpiece nearest said one end andbeing releasable therefrom to permit that workpiece to pass through saidopening, wherein the locking device comprises a locking member providedwith a projection, the projection being in alignment with, and passablethrough, an aperture provided in the magazine adjacent said one end, andthe free end of the projection being engageable with said workpiece.

Advantageously, the locking member is mounted on a pivotal lever whichis spring biased so as to force the projection through said aperture andinto engagement with said workpiece. Preferably, the lever is engageableby means of a cam surface provided on the loading device of the feedingapparatus for pivoting the lever against the biasing force of thespring, thereby releasing said workpiece from the magazine.

Embodiments of the invention will now be described, by way of example,with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic elevational view of a lens lathe fitted withautomatic loading and unloading devices constructed in accordance withthe invention;

FIG. 2 is a perspective view of the loading device of FIG. 1;

FIG. 3 is an enlarged view of part of the loading device of FIG. 2, andshows a pair of star wheels forming part of the loading device;

FIG. 4 is a part-sectional elevation taken on the line A--A of FIG. 2;

FIG. 5 is a view taken in the direction of the arrow X shown in FIG. 4.

FIG. 6 is view similar to that of FIG. 5, but showing a modifiedarrangement;

FIG. 7 is a perspective view of a modified form of piston-and-cylinderdevice suitable for use with the loading device of FIG. 2;

FIG. 8 is a perspective view of the magazine;

FIGS. 9A, 9B, 9C and 9D are elevations of chucks and blocks showing theshapes of the machined lens at different stages in its production; and

FIG. 10 is a flow diagram indicating the manufacturing operation.

Referring to the drawings, FIG. 1 shows a lens lathe similar to thatdescribed in British Patent Specification No. 1,488,001. The lathecomprises a turntable 1, on which tool holders (such as 2) are mountedfor machining a workpiece held in the collet 3 of the lathe. The collet3 is rotatably mounted by an air bearing in the head stock (not shown)of the lathe. A loader, indicated generally by the reference numeral 4,and an unloader, indicated generally by the reference numeral 5, areboth mounted on a plate 6. The plate 6 is hinged to the lathe so as tobe pivotable away from the lathe to facilitate replacement and settingof the tools.

The construction of the loader 4 is shown in FIGS. 2 to 5. Referring toFIG. 2, the workpieces are held in a magazine 10, which is releasablyheld by means (not shown) on the plate 6. The workpieces are removablesequentially from one end 11 of the magazine 10 by means of a loadingdevice 12. The loading device 12 is pivotably mounted by a shaft 13 on aplate 14 which is secured to the back plate 6. The loading device 12 isprovided with a loading head 15. A pair of star wheels 16 are mounted onthe loading head 15, the star wheels being arranged to grip theworkpieces in a manner which will be described later. Each of the starwheels 16 has five points, though it would be possible to use, forexample, four-pointed star wheels or six-pointed star wheels. Theloading head 15 is carried by a fork 17. The fork 17 is attached to acarriage 18, which is mounted for movement in an upward or downwarddirection on a slide 19. A fluid-operated piston-and-cylinder device 20is connected to the slide 19, and is capable of pivoting the assemblycomprising the slide 19 and the loading head 15 about the shaft 13 underthe control of a cam 21 and a cam surface 22. A piston-and-cylinderdevice 23 provides the power for moving the carriage 18 upwardly anddownwardly on the slide 19. Proximity switches 24 and 25 are locatedadjacent to the cam surface 22 for control purposes which will becomeclear later. The collet 3 of the lathe is shown diagrammatically in FIG.2.

The construction of the loading head 15, and the manner in which theworkpieces are removed from the magazine, is shown more clearly in FIGS.3, 4 and 5. Referring to FIGS. 4 and 5, the loading head 15 comprises apair of assemblies consisting of star wheel support plates 30, which arepivotably mounted on shafts 31, and are biased towards each other by aspring 32. The star wheels 16 are mounted on their respective supportplates 30 by one-way (free-wheel) clutches 33 such as Torringtonclutches. The star wheels 16 are free to rotate in the directions shownby the arrows in FIG. 3. A positioning lever 34 is pivotably mounted onthe loading head 15 (or on the carriage 18), and is spring biased in thedirection indicated by the arrow Y in FIG. 4. The lever 34 is providedwith an arm 35 having an accurately-machined gauging or feeler surface36. The position of the surface 36 is set so as to predetermineaccurately the position of a workpiece at the beginning of the loadingcycle.

The magazine 10 is loaded with workpieces, each of which is constitutedby a lens blank 37 mounted on a metal chuck 38 (see FIGS. 4, 8 and 9A).The magazine has a tubular casing of rectangular cross-section andconveniently holds about ten workpieces. The housing may be closed atone end and open at the other but preferably is open at both ends buthas a stop or a depression formed in the wall of the housing at the endopposite from which the chucks are removed. Conveniently the housing isextruded from a tough plastics material, such as p.v.c. The chucks 38each have an accurately-machined surface for contacting the gaugesurface 36 of the lever 34. The chuck 38 nearest to the open end 11 ofthe magazine 10 is held in place by a projection 39. The projection 39has a spherical surface which projects through a slot (or a hole) in thewall of the magazine 10, and engages in a similarly shaped recess 91(shown in dotted lines in FIG. 9A) in the end of the chuck 38. Theprojection 39 is mounted on a block 40, which is biased into engagementwith the recess in the chuck 38 by a spring 41. The block 40 isconnected to a hook 42 engaged by a pin at the end of a lever 43. Thelever 43 is pivoted about a shaft 44 and is operated by a cam surface(not shown) on the loading device 12. This cam surface is arranged, atthe appropriate time, to pivot the lever 43 in the direction of thearrow Z, thereby releasing the workpiece from the magazine 10.

FIG. 9A shows a chuck 38 and lens blank 37 in greater detail. As can beseen, the chuck 38 is formed with an annular groove 92 which isengageable by the star wheels of the loading and unloading devices. Lensblank 37 is bonded to the chuck by means of a thermoplastic adhesive,such as a wax adhesive, so that the partly machined blank can be removedat a later stage by raising the temperature of the chuck.

The unloader 5 is identical to the loader 4, except that its star wheelsare mounted on its support plates by one-way clutches which permit freerotation of the star wheels in the directions opposite to those shown bythe arrows in FIG. 3. Moreover, as the unloader 5 does not need toposition the workpieces, it is not provided with a positioning arm 34.

The manner in which the apparatus operates is as follows:

The operation is initiated by downwards movement of the carriage 18,under the influence of the piston-and-cylinder device 23. This causesthe magazine opening lever 43 to allow the lowermost workpiece to dropout of the magazine 10 and between the star wheels 16 of the loader 4.The chuck 38 of this workpiece contacts the surface 36 of the lever 34,which locates the chuck between the star wheels 16 accurately inrelation to the carriage 18. The carriage 18 is then moved down theslide 19 by the piston-and-cylinder device 23, while the cam 21 ispressed against the cam surface 22 by the piston-and-cylinder device 20.When the cam 21 reaches the microswitch 25, the piston-and-cylinderdevice 20 is actuated to pivot the carriage 18 about the shaft 13, andthereby to feed the chuck 38 into the collet 3 of the lathe. Then, assoon as the cam 21 hits the microswitch 24, the carriage 18 begins tomove upwards away from the collet 3 under the influence of thepiston-and-cylinder device 23; and, because the star wheels 16 are freeto rotate in the directions indicated, the chuck 38 is released from thestar wheels, and remains in the collet of the lathe.

The lens blank 37 carried by the chuck 38 can then be machined. Usuallythis will involve a first centering cut, followed by a traversing cut tomachine the base curve of the lens. A further tool will then plunge into cut the edge of the lens so that the partly machined lens has theappearance indicated in FIG. 9B. These machining operations aredescribed in British Patent No. 1,488,001. When this has been done, theunloader 5 moves downwardly to grip the chuck 38, and to remove thechuck from the lathe collet 3. The operation of the unloader 5 isidentical to that of the loader 4, except that it is in reverse. Theunloader 5 includes a magazine similar to the magazine 10; and, whenthis magazine is full, it can be removed and transferred to anothermachine, where a subsequent operation (such as edge polishing) isconducted. The edge polishing machine may have automatic loading andunloading mechanisms similar to those described above. The edgepolishing machine may comprise a horizontal table arranged to be rotatedin stepwise manner between stations. At a loading station, a loadingdevice such as that described later in relation to FIG. 6, but mountedhorizontally in a plane adjacent to that of the table is arranged tofeed chucks and attached lenses sequentially to holders on the table.When the table indexes to the next station, the edges of the partlymachined lens are polished by a rotating pad to which an abrasivesuspension is applied. In timed sequence, to correspond with the degreeof polishing required, the table indexes once more so that the polishedpart-machined lens moves to a station where an unloading device islocated. This is also arranged in a horizontal plane and is similar tothe device of FIG. 6 except that the one-way clutches operate in theopposite direction and no positioning device is necessary.

As soon as the first workpiece has been removed from the lathe collet 3by the unloader 5, the next workpiece can be removed from the magazine10 of the loader 4, and the cycle of operations described above can berepeated.

It will be apparent that a number of modifications could be made to theloading and unloading mechanisms described above. For example, thepositioning lever 34 could be replaced by a less bulky device. Thus,FIG. 6 shows the loading head 15 provided with a positioning device 34'in place of the lever 34. The loading head 15 is essentially the same asthat shown in FIG. 5 apart from the replacement of the positioning leverby the positioning device 34', and the fact that its star wheels 16 areof six-point construction. The positioning device 34' has a stop pin 45resiliently mounted within a housing 46. The housing 46 is fixedrelative to the magazine (not shown in FIG. 6), and the stop pin 45 ispositioned so as to contact a side face of one of the points of theleft-hand (as shown in FIG. 6) star wheel 16. The device 34' ispositioned so as to predetermine accurately the position of a workpieceat the beginning of a loading cycle. Thus, at the beginning of a loadingcycle, the loading head 15 is moved to the position shown in FIG. 6, inwhich the pin 45 contacts a side face of one of the points of theleft-hand star wheel 16. The magazine opening lever 43 (not shown inFIG. 6) is then operated to allow the lowermost workpiece to drop out ofthe magazine and between the star wheels 16. The remainder of theloading cycle is then the same as that described above with reference tothe embodiment of FIGS. 1 to 5. The pin 45 is resiliently mounted in itshousing 46 in such a manner as to minimise damage if, for any reason,the device 34' is incorrectly positioned, and the pin is subject toexcessive force on contacting the star wheel 16.

Although the positioning device 34' of FIG. 6 does require a morecomplicated setting-up procedure than the positioning lever 34, it hasthe major advantage of being considerably less bulky than thepositioning lever.

In another modification, the proximity switches 24 and 25 of theembodiment of FIGS. 1 to 5 are replaced by an arrangement utilisingmagnets and sensors. Thus, FIG. 7 shows a modified piston-and-cylinderdevice 23 whose piston rod 47 is provided with a permanent magnet 48. Asensor 49 is fixed to the cylinder 50 of the device 23. The magnet 48 ispositioned in a complementary recess formed in the piston rod 47, sothat it is flush with the outer surface of the piston rod.Alternatively, the piston rod 47 may be formed with an annularmagnetised zone in place of the magnet 48. The other piston-and-cylinderdevice 20 (not shown in FIG. 7) is also provided with a magnet (or amagnetised zone) on its piston rod, and with a sensor on its cylinder.The magnets are positioned on their piston rods so that they are sensedby their sensors at the appropriate times in the loading cycle tofulfill the functions of the proximity switches 24 and 25. Thus, whenthe cam 21 reaches the end of the cam surface 22, the magnet 48 isaligned with the sensor 49, which actuates the piston-and-cylinderdevice 20. The device 20 then pivots the carriage 18 (see FIG. 2) aboutthe shaft 13, and so feeds the chuck 38 carried by the star wheels 16 tothe collet 3 of the lathe. Then, when the magnet and sensor of thedevice 20 are in alignment (that is to say when the cam 21 reaches theposition equivalent to that in which the microswitch 24 of theembodiment of FIGS. 1 to 5 was triggered), the piston-and-cylinderdevice 23 is actuated to move the carriage 18 upwards and away from thecollet 3. As with the embodiment of FIGS. 1 to 5, the chuck 38 isreleased from the star wheels 16, at this stage, because the star wheelsare free to rotate in the directions indicated in FIG. 3.

The sensor 49 may be provided with a delay switch 50 which delaysactuation of the piston-and-cylinder device 20 until the cam 21 hasmoved a short way downwards from the position shown in FIG. 2. Thisarrangement is advantageous in that it prevents the cam 21 from jammingagainst the start of the cam surface 22.

In a further modification of the embodiment shown in FIGS. 1 to 5, theloader 4 and the unloader 5 are fixed to the bed of the lathe, and thecollet/tool holder assembly is movable. This gives rise to a more stablearrangement.

After the partly machined lens (FIG. 9B) has been polished, the lens istransferred to a block 101 similar to chuck 38 except that it has arounded top 102 for receiving the base curve of the lens (see FIG. 9C).The necessary transfer is effected in a blocking machine in which achuck and attached part-machined lens is held on top of a heated blockto which a blob of hot adhesive wax is applied. When all threecomponents have cooled and are bonded together, the bond between thechuck 38 and the part-machined lens is broken. These operations can becarried out on a machine having an indexing table to which thepart-worked lenses are fed from magazines and removed on blocks intomagazines, using the same kind of loading and unloading devices asdescribed above in connection with the polishing machine.

FIG. 10 is a typical flow sheet for manufacturing lenses using machinesfitted with the automatic loading and unloading devices of thisinvention. Pre-formed blanks 37 (see FIG. 9A) are fed to the chuckingmachine by means of a vibratory feeder and are there bonded by athermoplastic wax adhesive to a metal chuck 38. The chucking machinecomprises a pair of horizontal tables to which the chucks and pre-formedbutton-shaped blanks are each fed by their respective vibratory feeders.Just before a chuck and blank are brought together a blob of hot wax isapplied to the top of the chuck. The resultant workpieces are indexedaround the second table until they reach the unloading station, wherethey are unloaded into a magazine (as shown in FIG. 8) using anautomatic unloading device operating horizontally, as previouslydescribed.

From the chucking machine the magazines containing workpieces aresupplied to the base curve lathe. The lathe operates as alreadydescribed to produce a partly worked lens 37B having the form indicatedin FIG. 9B and are unloaded into magazines after the base curvemachining steps. Magazines containing the partly worked lenses andchucks are then passed to a polishing machine where the edges aresubjected to a short polishing operation. As previously describedsimilar automatic loading and unloading devices are employed and thepartly worked lenses are again unloaded into magazines.

The next operation is the transfer of the partly worked lens to a metalblock 101 (see FIG. 9C). This transfer is carried out using a blockingmachine as described above. Again the partly-worked lenses (this timebonded the other way round to a metal block) are unloaded into amagazine and sent to a lens lathe, where the front or power curve iscut. The lathe is similar to that already described for cutting the basecurve. After this operation, the lens 37D (see FIG. 9D) is sent in amagazine to a second polishing machine from which the lenses andattached blocks are passed in magazines to the de-blocking machine,where the lenses are removed from the blocks by heating the blocks to atemperature at which the wax melts. At this point since the lenses havebeen separated from their blocks, they are guided individually to atesting and quality control location. If hard lenses are beingmanufactured, the lenses are then packaged. In the case of soft lenses,the products at this stage are sent to swelling and washing apparatus.

It will be appreciated that a system in which lens blanks or partiallymachined lenses are contained in a magazine from which the workpiecescan be fed to, or accepted from, a machine or apparatus has severaladvantages. For example, there is no individual handling of theworkpieces, either during machining or polishing, or in transporting theworkpieces from one machine to another in the different stages ofmanufacture. At the same time, the use of magazines enables flexibilityof production to be achieved, since partially worked lens blanks having,for example, the same base curve dimensions can be fed to differentmachines for cutting power curves of different sizes. The magazine maybe made from metal or plastics material, and may be marked to indicatethe characteristics of the workpieces which it contains. This may beachieved magnetically, for example by including a magnetic recordingstrip attached to the magazine on which the history (and/or the intendeddimensions) of the workpiece are recorded. The machines may be providedwith magnetic strip reading heads, which are programmed to accept onlymagazines which contain workpieces appropriate to the particular phaseof manufacture.

We claim:
 1. A method of manufacturing contact lensescomprising:enclosing a first lens blank which is mounted on a firstsupport and a second lens blank which is mounted on a second support ina first tubular protective magazine, unloading at a first station saidfirst mounted lens blank from said first tubular protective magazine,positioning said unloaded first mounted lens blank at a predeterminedlocation with respect to a collet of a first machine tool, saidpositioning including contacting a surface of said first support with asensing means which senses the position of said first support relativeto said collet, thereby sensing the position of said first supportrelative to said collet, feeding said first support with said firstblank lens mounted thereon from said predetermined location into saidcollet, machining said first lens blank with said first machine tool,thereby forming a partly-worked first lens blank, removing saidpartly-worked first lens blank from said collet, enclosing said removedpartly-worked first lens blank in a second tubular protective magazine,after said unloading step, unloading said second mounted lens blank fromsaid first tubular protective magazine, and machining said secondmounted lens blank with said first machine tool, thereby forming apartly-worked second lens blank, after said enclosing said removedpartly-worked first lens blank step, enclosing said partly-worked secondlens blank in said second tubular protective magazine, and thereafter,transferring said second tubular protective magazine to a second machinetool and unloading said first and second partly-worked lens blanks fromsaid second tubular protective magazine into a collet of said secondmachine tool and performing with said second machine tool a machiningoperation on said first and second lens blanks, and unloading said firstand second lens blanks from said collet of said second machine toolafter being machined by said second machine tool.
 2. The method of claim1 further comprising, before said enclosing a first lens blank step,mounting said first lens blank to said first support.
 3. The method ofclaim 2 wherein said mounting step includes adhesively bonding saidfirst lens blank to said first support with adhesive wax.
 4. The methodof claim 3 further comprising, after said transferring step, heatingsaid adhesive wax and separating said machined first lens blank fromsaid first support.
 5. The method of claim 4 wherein said heating stepis after said performing with said second machining tool a machiningoperation step.
 6. The method of claim 1 wherein said unloading saidfirst mounted lens blank step includes dropping said first mounted lensblank into gripping jaws positioned beneath said first tubularprotective magazine.
 7. The method of claim 1 wherein said unloadingsaid first mounted lens blank step includes dropping said first mountedlens blank into jaws formed by a pair of star wheels.
 8. The method ofclaim 7 wherein said positioning step further includes rotating saidpair of star wheels.
 9. The method of claim 1 wherein said machiningsaid first lens blank step comprises lathing said first lens blank. 10.The method of claim 1 wherein said machining operations comprisespolishing said first and second partly-worked lens blanks.
 11. Themethod of claim 1 wherein said machining operations comprises cuttingsaid first and second partly-worked lens blanks.
 12. The method of claim1 further comprising, after said unloading from said collect of saidsecond machine tool step, enclosing said first and second lens blanks ina third tubular protective magazine.
 13. The method of claim 12 furthercomprising, after said enclosing in a third tubular protective magazinestep, transferring said third tubular protective magazine to a polishingmachine, unloading said first and second lens blanks from said thirdtubular protective magazine, and polishing said first and second lensblank on said polishing machine.
 14. The method of claim 12 wherein saidenclosing said first and second lens blanks in a third tubularprotective magazine step includes said first and second lens blanksbeing mounted respectively to said first and second supports.
 15. Themethod of claim 12 further comprising, after said enclosing said firstand second lens blanks in a third tubular protective magazine step,separating said first and second lens blanks respectively from saidfirst and second supports.
 16. The method of claim 12 wherein saidenclosing said partly-worked second lens blank step includes said secondlens blank being mounted to said second support, and said enclosing saidfirst and second lens blank blanks in a third tubular protectivemagazine step includes said first and second lens blanks being mountedrespectively to said first and second supports.
 17. The method of claim1 wherein said transferring step comprises mechanically transferringsaid partly-worked first and second lens blanks from generally saidfirst machine tool to said second machine tool.
 18. The method of claim1 wherein said enclosing said first and second lens blank step comprisespositioning said first and second mounted lens blanks in said firsttubular protective magazine so that they are adjacent one another, andso that longitudinal axes thereof are parallel to each other andgenerally perpendicular to a longitudinal axis of said first tubularprotective magazine.
 19. The method of claim 1 wherein said unloadingfrom said second tubular protective magazine includes unloading saidfirst partly-worked lens blank to a predetermined collet location withrespect to said collet of said second machine tool, and thereafterunloading said second partly-worked lens blank to said predeterminedcollet location.
 20. The method of claim 1 wherein said enclosing saidpartly-worked second lens blank step includes said second lens blankbeing mounted to said second support.
 21. The method of claim 1 furthercomprising after said enclosing said partly-worked second lens blankstep, separating said second lens blank from said second support.